The five original objectives of this Group provide high quality comprehensive mathematical biology and computational support to CHAVI. Aim 1 is to develop novel methods for analysis of neutralizing antibody data. Aim 2 is to develop phylogenetic tools for defining sequence correlates of biological characteristics. Aim 3 is to support the structural biology program of CHAVI, the CHAVI B cell immunology and the vaccine design discovery teams. Aim 4 is to provide the CHAVI sequence database analysis and support for all components of CHAVI. Aim 5 will provide CTL peptide design for the T cell program. Aim 6 was added in year two, and Alan Perelson was brought into the program to lead a mathematical modeling component of the project, to model primary infection, the immune response to infection, and the impact of vaccines